Conventionally, there are known various caps for wiring pass-through hole adapted to cover the wiring pass-though hole provided in a wall of a desk or the like and an example of the commercial available caps is illustrated in FIGS. 5(A) and 5(B). The cap a comprises a diameter-reduced engagement cylindrical part b fitted into the wiring pass-through hole B previously provided in a top board A of the desk D and a removal prevention peripheral edge cover part c for engaging the upper surface of the top board A. This cap a is attached to the top board A by the diameter-reduced cylindrical part b and the peripheral edge cover part c thereof. As understood from FIG. 5(B), the removal prevention peripheral edge cover part c is provided with a partially opened wiring pass-through opening d and an outer peripheral surface of the diameter-reduced cylindrical part b is provided with a plural of removal prevention peripheral striped protrusions e.
The conventional cap a for wiring pass-through hole is just loosely fitted into the wiring pass-through hole b in the top board A and therefore if this cap tries to be fitted into the wiring pass-through hole b provided in a vertical wall such as the side board, then the cap will be possibly reluctantly removed out of the side board due to vibration or other outer force applied thereto.
There is disclosed in Patent Document JU 7-24135 a cap for wiring pass-through hole suitable for being used for the side board of the desk or the like in which the aforementioned disadvantage is avoided and the brief construction thereof is illustrated in FIG. 6.
As shown in FIG. 6, the cap is provided with a duct f disposed along the bottom side of the top board of the desk D and both ends of the duct f are supported on both of the side boards g and k of the desk D while both ends of the duct f are faced to the wiring pass-through holes h provided in the side boards so as to be faced to each other. The frame-like cap i is inserted into the wiring pass-through hole h in one of the side boards g until an attaching frame portion i fully enters one of the ends of the duct f and then the frame-like cap i is fitted into the other wiring pass-through hole h in the other side board k in the same manner.
Since the caps having the construction of FIG. 6 are fitted into the duct f extending between the side boards g and k, they never fall out of the side boards g and k, but the wiring cord or cords have to pass through the duct f, which causes the flexibility to be restrained and the convenience for use to be deteriorated.
An object of the invention is to provide a cap for wiring pass-through hole adapted to be easily used not only on a horizontal surface of a top board or the like, but also on a vertical surface of a side board or the like by avoiding the disadvantage of the conventional cap for wiring pass-through hole.